source: proiecte/PPPP/eigenface/camshift_wrapper.c @ 28

// camshift_wrapper.c - by Robin Hewitt, 2007
// http://www.cognotics.com/opencv/downloads/camshift_wrapper
// This is free software. See License.txt, in the download
// package, for details.
//

#include "cv.h"
#include <stdio.h>
#include "camshift_wrapper.h"


// Parameters
int   nHistBins = 30;                 // number of histogram bins
float rangesArr[] = {0,180};          // histogram range
int vmin = 65, vmax = 100, smin = 55; // limits for calculating hue


// File-level variables
IplImage * pHSVImg  = 0; // the input image converted to HSV color mode
IplImage * pHueImg  = 0; // the Hue channel of the HSV image
IplImage * pMask    = 0; // this image is used for masking pixels
IplImage * pProbImg = 0; // the face probability estimates for each pixel
CvHistogram * pHist = 0; // histogram of hue in the original face image

CvRect prevFaceRect;  // location of face in previous frame
CvBox2D faceBox;      // current face-location estimate


int nFrames = 0;


// Declarations for internal functions
void updateHueImage(const IplImage * pImg);


//////////////////////////////////
// createTracker()
//
int createTracker(const IplImage * pImg)
{
        // Allocate the main data structures ahead of time
        float * pRanges = rangesArr;
        pHSVImg  = cvCreateImage( cvGetSize(pImg), 8, 3 );
        pHueImg  = cvCreateImage( cvGetSize(pImg), 8, 1 );
        pMask    = cvCreateImage( cvGetSize(pImg), 8, 1 );
        pProbImg = cvCreateImage( cvGetSize(pImg), 8, 1 );

        pHist = cvCreateHist( 1, &nHistBins, CV_HIST_ARRAY, &pRanges, 1 );

        return 1;
}


//////////////////////////////////
// releaseTracker()
//
void releaseTracker()
{
        // Release all tracker resources
        cvReleaseImage( &pHSVImg );
        cvReleaseImage( &pHueImg );
        cvReleaseImage( &pMask );
        cvReleaseImage( &pProbImg );

        cvReleaseHist( &pHist );
}


//////////////////////////////////
// startTracking()
//
void startTracking(IplImage * pImg, CvRect * pFaceRect)
{
        float maxVal = 0.f;

        // Make sure internal data structures have been allocated
        if( !pHist ) createTracker(pImg);

        // Create a new hue image
        updateHueImage(pImg);

        // Create a histogram representation for the face
    cvSetImageROI( pHueImg, *pFaceRect );
    cvSetImageROI( pMask,   *pFaceRect );
    cvCalcHist( &pHueImg, pHist, 0, pMask );
    cvGetMinMaxHistValue( pHist, 0, &maxVal, 0, 0 );
    cvConvertScale( pHist->bins, pHist->bins, maxVal? 255.0/maxVal : 0, 0 );
    cvResetImageROI( pHueImg );
    cvResetImageROI( pMask );

        // Store the previous face location
        prevFaceRect = *pFaceRect;
}


//////////////////////////////////
// track()
//
CvRect track(IplImage * pImg)
{
        CvConnectedComp components;

        // Create a new hue image
        updateHueImage(pImg);

        // Create a probability image based on the face histogram
        cvCalcBackProject( &pHueImg, pProbImg, pHist );
    cvAnd( pProbImg, pMask, pProbImg, 0 );

        // Use CamShift to find the center of the new face probability
    cvCamShift( pProbImg, prevFaceRect,
                cvTermCriteria( CV_TERMCRIT_EPS | CV_TERMCRIT_ITER, 10, 1 ),
                &components, &faceBox );

        // Update face location and angle
    prevFaceRect = components.rect;
        faceBox.angle = -faceBox.angle;
        //cvEllipseBox(pImg, faceBox,
        //                               CV_RGB(255,0,0), 3, CV_AA, 0 );
        return prevFaceRect;
        //return faceBox;
}


//////////////////////////////////
// updateHueImage()
//
void updateHueImage(const IplImage * pImg)
{
        // Convert to HSV color model
        cvCvtColor( pImg, pHSVImg, CV_BGR2HSV );

        // Mask out-of-range values
        cvInRangeS( pHSVImg, cvScalar(0, smin, MIN(vmin,vmax), 0),
                    cvScalar(180, 256, MAX(vmin,vmax) ,0), pMask );

        // Extract the hue channel
        cvSplit( pHSVImg, pHueImg, 0, 0, 0 );
}


//////////////////////////////////
// setVmin()
//
void setVmin(int _vmin)
{ vmin = _vmin; }


//////////////////////////////////
// setSmin()
//
void setSmin(int _smin)
{ smin = _smin; }